This invention relates to methods for changing sizes of pant-type personal care articles outputted from a manufacturing process. More specifically, this invention relates to methods for changing sizes in especially the circumferential waist components of pant-type refastenable personal care articles. The methods of the invention attenuate the counterproductive aspects of down time on manufacturing lines to change and adjust function rolls and other components necessary for changing production from first articles having a first waist size to second different articles having a second different waist size, of pant-type, especially refastenable, absorbent personal care articles.
In conventional methods for fabricating disposable pant-type personal care articles of differing sizes, it is known to stop manufacturing line production of personal care articles of a first size to one or both replace and reposition function rolls and adjust timing of manufacturing line components to produce personal care articles of a second different size on the same manufacturing line. The down time associated with a conventional such production change-over is typically significant. The main reason for such significant down time is related to conventional methods of changing the product length, also known as repeat length, in order to effect change in product (e.g. waist) size.
In such conventional size change-over, function rolls are typically either exchanged, or moved in the machine direction along the manufacturing line, to accommodate changes in lengths of, for example, front portions and back portions of such personal care articles, defining first and second different waist sizes thereby to define respective first and second sizes of such pant-type personal care articles. Similarly, other manufacturing components are typically adapted to such size changes while the manufacturing process is stopped. For example, knife repeat distances may be adjusted, or a knife or knives may be moved, to compensate for changed cutting requirements. Timing of front fastener panel application and/or hook tab fastener application may also need to be adjusted in the machine direction to compensate for waist size differentiation between different sizes of personal care articles. In sum, the conventional method of making a size change is to shut down the production line and, while production is shut down, to physically adjust or move selected machines and/or other mechanical devices in order to effect the change to making a second different size of personal care article.
A need exists for improved methods for production of pant-type personal care articles wherein the methods are effective to attenuate down time for effecting size changes on a manufacturing line as well as to reduce cost to manufacturers by enabling manufacturers to use manufacturing line components in common to produce pant-type personal care articles in both first and second sizes.
Thus, it is an object of this invention to provide methods for production of pant-type personal care articles in both first and second sizes on a manufacturing line while attenuating down time.
It is a further object to provide manufacturing processes which reduce cost to manufacturers by enabling a manufacturer to use the same manufacturing line components in producing first and second sizes of pant-type personal care articles.
It is another object to provide a manufacturing process wherein the manufacturing process can be changed to produce a second different size pant-type personal care article without shutting down the manufacturing process for a significant duration of time.
It is yet another object to provide methods wherein workpieces, including a defined length of material, have a common dimension, leading edge-to-leading edge, in the machine direction of the manufacturing process both with inclusion of the length of material and with exclusion of the length of material.
In a first family of embodiments, the invention comprehends a method of changing from manufacture of pant-type refastenable personal care articles of a first size to manufacture of such pant-type refastenable personal care articles of a second different size. The method takes place in a process for manufacturing pant-type refastenable personal care articles in a format which includes defining a stream of workpieces connected to each other along a web having an indefinite length. A respective such personal care article has a front portion, a rear portion, and a crotch portion. The method comprises, with respect to each workpiece, defining in the web or workpiece a length of material defined in the machine direction wherein activity of such length of material, in combination with other elements of the web or workpiece, determines the size of the pant-type refastenable personal care article being so produced, whereby the length of material can be activated to thereby produce relatively larger such personal care articles, or inactivated to produce relatively smaller such personal care articles. The method also comprises changing activity of the lengths of material so defined, thereby to affect size change in the respective personal care articles being produced while maintaining the so-defined lengths of material in the web at least until the respective workpieces are separated from the web.
In some embodiments, the method includes such workpieces, including the defined length of material, having a common dimension, leading edge-to-leading edge, in the machine direction of such manufacturing process both with inclusion of the length of material and with exclusion of the length of material.
In preferred embodiments, first and second side seam bonds are formed on opposing sides of respective ones of adjoining workpieces, and inboard edges of adjacent side seam bonds on adjacent workpieces are spaced from each other by a first distance. In such embodiments, the method further includes changing the activity of the length of material by manufacturing workplaces having the inboard edges of adjacent such side seam bonds spaced from each other by a second distance different from the first distance.
The invention can include inactivating the length of material by manufacturing workpieces having the inboard edges of adjacent such side seam bonds spaced from each other by a second distance greater than the first distance.
In some embodiments, the method includes changing timing and thus location of forming of side seam bonds on the respective workpieces, in combination with timing and thus location of formation of cuts separating such workpieces from the web, thereby effecting a size change in the personal care articles being so produced, sufficient in magnitude to be discernable in routine consumer sales.
In other embodiments, the method includes changing one or both timing and loci of side seam bonder apparatus components, and thus location of formation of side seam bonds on the respective workpieces, in combination with changing one or both timing and loci of separation apparatus components, and thus location of formation of cuts separating such workpieces from the web while continuing ongoing production of such personal care articles.
In a second family of embodiments, the invention comprehends the length of material so defined being activated and thereby incorporated into the personal care article to correspondingly produce a relatively larger such personal care article, or inactivated and thereby excluded from the personal care article to correspondingly produce a relatively smaller personal care article.
In preferred embodiments, the method includes defining first and second such lengths of material at opposing first and second such side edges of the respective workpiece, and controlling activity of such lengths of material thereby to determine the size of the respective pant-type refastenable personal care article.
In some embodiments, the method includes changing one or both timing and loci of side seam bonder apparatus components, and thus location of forming of side seam bonds on the respective workpieces from the web, and thereby effecting a size change in the personal care articles being so produced, sufficient in magnitude to be discernable in routine consumer distribution.
In a third family of embodiments, the invention comprehends a method wherein each workpiece has bonds joining the front portion and the rear portion to each other at the side edges, and each such bond has an inwardly-disposed edge disposed away from the respective side edge of such workpiece. The method comprises with respect to each workpiece, defining in the web or workpiece, at the side edges of the respective workpiece, a length of material defined in the machine direction, wherein incorporation of such length of material, in combination with other elements of the web or workpiece, inwardly of the inwardly-disposed edges, produces a pant-type refastenable personal care article of a relatively larger size, and wherein exclusion of such length of material from the workplace produces a pant-type refastenable personal care article of a relatively smaller size; and changing use of the lengths of material so defined, from inclusion to exclusion or from exclusion to inclusion, thereby to effect size change in the respective personal care articles being produced while maintaining the so-defined lengths of material in the web at least until the respective workpieces are separated from the web.
In a fourth family of embodiments, the invention comprehends a method including initiating such manufacturing process and thereby beginning manufacture of an ongoing stream of such personal care articles. The method includes, while continuing to manufacture the ongoing stream of such personal care articles, changing activity of part or all of ones of the lengths of material so defined, thereby to effect a size change in the respective personal care articles being produced.
The method can include separating successive ones of the workpieces from the web, and separating the inactivated lengths of material from both of the adjacent respective workpieces.
In some embodiments, the method includes employing a programmable logic computer to instruct bonding apparatus regarding one or both proper timing and positioning of bonder components, and thus location for forming the side seam bonds. The method can also include employing a programmable logic computer to instruct separation apparatus regarding one or both proper timing and positioning of separator components, and thus location on the workpieces for separation of the respective workpieces from the web, and from the inactivated lengths of material.